QUOTE(DJBPace07 @ Nov 18 2009, 09:30 PM)

I've never heard of OEM's actually soldering cables onto the motherboard, I have heard of them having special proprietary connectors, though.
An old pre made Packard Bell I used to have had the Power and Reset buttons soldered to the motherboard, was epic fail! It's the only time I've ever seen it myself, wouldn't have believed it unless I saw it :D
Anyway for dirt cheap $600 you could roll with this. The mobo is a micro atx, but I think you'll probably want as cheap as you can get while been a good performer. The CPU is a quad core, so it should last you a few years. And the GPU is more than enough for CoD:MW2. It's DX11 capable aswell!
You could maybe re-use your hard drive, but as DJBPace said, it's probably nearing it's end, not to mention it's probably quite slow, and very little space on it. I recommend you get a new one too!
Here's what I got at $600, if you're willing to spend more you can get a better system. Also a wee note if you've never built before, it's a very easy process! Youtube has lots of videos, and if you watch them you'll see how easy it is, if you can change the RAM/GPU on your current computer it's just as easy to assemble the rest!

Left click and click view at full size.
p.s: No operating system in there, you can use your windows xp if you want, or get the OEM copy of W7 for around $100. Also, if it's needs to be cheaper, parts can be changed, namely the GPU+CPU.